Dolly retainer



July 6. 1926. 1,591,620

, H. V. HAIGHT DOLLY RETAINER Filed Oct. 14, 1925 IN VEN TOR.

H l lfai [at BY 2] #15 MT E 1 Patented July 6, 1926.

UNITED STATES PATENT orrics.

HARRY V. I'IAIGIT'I, Oil SHERBEOGKE, QUEBEC, CANADA, ASSEGEIGR T6 EIETGERS'OLL- RAND COMPANY, OF JERSEY CITY, i f-ENV JERSEY, A CORPORATION 013" NEW JERSEY.

D'QLLY RETAINER...

Application filed October 14, 1925.

The objects of the invention are to construct a rugged and simplified dolly retainer, capable of withstanding the severe usage to which such retainers are sub ected, to lessen the chances of breaking in retainersv of this type and to employ pressure fluid in combination with spring means for holding the dolly in. operative position- .v

Other objects will-be in part obvious and in part pointed out hereinafter.

The invention consists of the combinations of elements, features of construction and arrangement of parts having the gen? eral mode of operation, substantially as hereinafter described and more particularly pointed. out in the appended claim and. illus trated in the accompanying drawings, in which- Figure 1 is a sectional view in elevation of portion ofa drill sharpener showing the retainer secured to the front head,

Figure 2 is an: end view partly in section of the front head of a drill sharpener illustrating the manner in which the retainer is clamped on the front head, and

Figure is a side view of the front head and the retainer showing the retaining member in releasing position.

Referring to the drawings, in which only so much of a drill sharpener is shown as will serve to illustrate the invention and its application, a cylinder A supports a front head B and is provided with a reciprocatory hammer piston C. The hammer piston C has a plain forward extension D slidable through a front cylinder washer E and is adapted to reciprocate within a bore F of the front head B. Disposed slidably in the front head B is a dolly H having a. reduced rearward extension J which projects at its end into the bore F of the front head B to receive the blows of the hammer piston C. A port G is formed in the front head B to provide communication between the bore F and the atmosphere in order to prevent the formation of a cushion in the bore F.

In this instance the outer or forming face K of the dolly H. is of star shaped formation to form a corresponding face on the end of a drill steel (not shown) and which drill steel may be securely held by suitable devices independent of the drill sharpener. It is, however, to be understood that the dolly illustrated in the drawings does not Serial No; 62,399;

form any part of the invention and is shown merely for illustrative purposes.

ln accordance with the practice of the invention, a cylinder L is disposed onthe free end of the front head B and is preferably formed integrally with aclam-p O having a bore P to receive the front head 13 Any suitable means may be provided for tightening the clampon the front head, but such means preferably consists of; a bolt Q having a eyirndrical head- R with a flattened surface S formed on one side of the head to cooperate with a lug T carried by the clamp for preventing turning of the bolt Q when anut U is being screwed on the end of the bolt. A bracket V carried by the cylinder L is bored: to receive a bolt N which serves as a: pivot for a bell crank or cranks X havtug arms Y an d Z. The arms Y of the bell cranks X are connected at corresponding P ends by means of a rod or pin 6'. The pin 7 may be secured against displacement from the arms Y in any suitable mannerand is adapted to cooperate with a slot 0 formed transversely through the dolly H... In a'did-i tion to serving as a means for engaging the dolly l-Lthe pin 6 also provides rigidity to the bell cranks X so that said bell cranks will oscillate about the pivot W in unison. A similar pin (Z is supported by the arms Z and extends through the cylinder L through, slots 6 on opposite sides of said cylinder.

Disposed within the cylinder L is a hollow piston 7 provided with a spring 9 which constantly tends to force the piston f outwardly against the pin (Z to oscillate the bell cranks X about the pivot W for holding the dolly H within the front head, as indicated in Figure 1.

Normally when the machine is inoperative the pressure of the spring 9 will be sufiicient to hold or retain the dolly within the front head, but when the machine is in operation, the rapid delivery of blows of the hammer piston against the dolly will subject the spring 9 to excessive strains and cause early breakage of the spring as has been frequently experienced in similar devices. In order to protect the spring 9 against such shocks, a port it is formed in the cylinder L for admitting pressure fluid into said cylinder. Presure fluid for actu" ating the piston f is supplied to the port it through a suitable connection j. The admission of pressure fluid into the cylinder L may be controlled in any well known and suitable manner. The cylinder L may have separate controlling means or may be so connected that pressure fluid will be ad mitted or supplied thereto simultaneously with the admission of pressure fluid to the percussive element of the sharpener.

It will be seen from the foregoing description that the pressure fluid thus admitted into the cylinder L will serve as a cushion for absorbing blows of the piston C against the dolly H.

Although only a plain pi'n d is shown connecting the arms Z to cooperate with the piston f, it is to be understood that, if desired, a roller in the form of a tubular member or other well known means may be arranged loosely about the pin d in order to eliminate wear on the pin (Z and the piston This invention has been found to be unusually durable and efiicient in operation. It may be readily attached to machines now in operation without requiring any material alterations thereto, and by utilizing pressure fluid as a cushioning means for absorbing jars and shocks, the breakage of the retaining springs has been eliminated. An other desirable feature is that this construction permits the use of a spring of greater flexibility than would be the case if only a spring were used for cushioning the retainer so that less difficulty is experienced in connecting the retaining member with the dolly .and disconnecting said member therefrom.

In removing the dolly H from the front head B, the dolly may be pulled out of the front head which will carry the bell cranks to the position shown in dot and dash lines. When the dolly reaches this position the pin 6 will be rocked out of the slot 0 and the dolly may be removed from lhe front head. To insert the dolly in the front head, the bell cranks may be rocked to the position shown in dot and dash lines and the dolly may then be inserted until the slot 0 is directly beneath the pin 6, whereupon the bell cranks may be released and the pin will be rocked into the slot and automatically move the dolly in position for the succeeding operation.

I claim:

In a dolly retainer for a drill sharpener having a front head and a dolly slidable in the front head, the combination of a cylinder, a clamp on the cylinder for securing said cylinder to the front head, a bracket integral with the cylinder, a bell crank mounted pivotally on said bracket and in constant engagement with the dolly, a piston in the cylinder associated with the bell crank, a port in one end of the cylinder for admitting pressure fluid into said cylinder whereby the piston and the bell crank are actuated in one direction for retaining the dolly in the front head, and a spring acting against the piston for constantly holding the bell crank in retaining position.

In testimony whereof I have signed this specification.

HARRY V. HAIGHT. 

